The repaired TCL color TV NT21228 customer responded to the power switch, and it could not be seen after a period of time. When I came to the door, the indicator light was on, the remote control and the buttons could not be turned on, and then the set-top box was opened without any indication. I thought that the machine was struck by lightning and the owner agreed to take it home for repair. 3 Inch Compression Driver,Professional Horn Driver,3 Inch Titanium Tweeter,Neodymium Driver Guangzhou BMY Electronic Limited company , https://www.bmy-speakers.com
I looked at the motherboard roughly, and the copper foil was blown, but it was not very serious. Check that the two triodes connected to it were damaged to varying degrees. Replace them and connect them to the shortcomings. The fault is not eliminated. Measuring +B is 35V, obviously in standby mode. Check SCL and SDA voltage are about 4V, remove the memory block, the voltage is unchanged, pick up the large SCL and SDA feet, 5V voltage is normal, the main chip is damaged, no doubt, buy back OM8370PS/N3/1/1680 with socket At the same time, the memory block was changed, the button was turned on, and the sound was turned on.
The repair is not over, the conversion signal is input (the signal is not inserted at the time), the TV has no noise, the AV is black, and then the protection screen appears. If the AV is plugged in, there is no picture and no sound, and a voltage-stabilizing diode breakdown in the conversion circuit is found. The triode is damaged and the picture is normal after replacement.
After one hour of test machine shutdown with remote control, no response, use the phone camera function to confirm that the remote control is normal, turn it on again, take out the receiving board, measure that 5V is normal, the receiving tube terminal voltage is close to 0, and find that the power supply resistance turns black, replace this 100 Ohmic resistor and infrared receiver tube, this color TV repair is completed.
Replaced parts
Normal machine